Why Do People With Diabetes Get Foot Ulcers? Causes, Stages, and Pictures

Diabetes is a condition that affects many major systems in the body. Untreated diabetes can be deadly, but it can also cause significant illness and disability. This includes diabetic foot ulcers — a common issue in people with diabetes.

Up to 1 in 3 people with diabetes will have a foot ulcer during their lifetime. But finding them early and getting treatment right away can help them heal faster and lower the risk of complications.

What are diabetic foot ulcers?

Diabetic foot ulcers are open wounds on the sole of the foot and toes. They can appear as small red craters surrounded by thick, callused skin. But they can also advance to a severe infection with a very large wound. Foot ulcers are more common in untreated or undertreated diabetes. 

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Diabetes can lead to foot ulcers because of:  

• Decreased sensation in the feet from nerve damage

• Problems with sweat production, which makes feet more likely to develop dryness and skin cracking

• Trouble with wound healing

• Decreased blood flow to the legs and feet 

What are the symptoms of a diabetic foot ulcer?

Symptoms of a diabetic foot ulcer can vary based on how severe the wound has become. Common symptoms of a diabetic foot ulcer that you should keep an eye out for include:

• Changes to the skin or toenails

• Large calluses or cracked heels

• Drainage of fluid, pus, or blood

• Foul smell

• Pain

• Redness

• Skin discoloration

• Swelling

A foot ulcer isn’t always painful if you have diabetes. That’s why it’s important for you to look at your feet daily for blisters, cuts, and cracks. Any changes in your feet or toes should raise suspicions for a diabetic foot ulcer. And you should get medical care right away.

Pictures of diabetic foot ulcers

Here are some pictures of diabetic foot ulcers in different skin tones. 

A diabetic foot sore (left) and a developed ulcer (right) are in its early stages.

A diabetic foot sore develops on the ball of the foot.

What factors raise the risk of diabetic foot ulcers?

Diabetes alone is enough to place you at risk for a foot ulcer, especially if you’ve had a diagnosis of diabetes for more than 10 years. Other health conditions and factors that raise your chances of an ulcer include:

• High blood pressure

• Heart disease

• Kidney disease

• Eye disease from diabetes

• Obesity

• Older age

• Being born male

• Poorly fitted shoes

• Improper trimming of toenails

• Alcohol consumption

• Tobacco use

How can you prevent foot ulcers?

There are steps you can take to lower your chance of developing diabetic sores on your feet. If you have diabetes, you can help prevent foot ulcers by: 

• Inspecting your feet daily: Look for blisters, cuts, scratches, or ingrown toenails. If it’s hard for you to check out your own feet, ask someone else to do it. 

• Wearing proper footwear: Wear shoes that aren’t too tight or too loose. Avoid walking barefoot, wearing sandals, or using high heels. 

• Monitoring blood sugar levels closely: Keeping your blood sugars in a healthy range can help with wound healing. 

• Quitting smoking: Cigarettes and other tobacco products make it harder for your skin to heal wounds. 

• Lowering weight: If you have excess weight, losing weight may help put less strain on your feet and may lower your chances of developing a foot ulcer. 

EXPERT PICKS: WHAT TO READ NEXT

• Diabetes and foot pain: Learn how to prevent and treat diabetic neuropathy. 

• Treatments for diabetic foot ulcers: From wound dressings to hyperbaric oxygen therapy, there are multiple ways to help your ulcer heal. 

• Complications of diabetes: Learn about long-term complications of diabetes beyond foot ulcers — and how to lower your risk.

How are foot ulcers diagnosed?

Foot ulcers are usually diagnosed through a combination of a medical history, physical exam, and other tests. When you see changes in your feet, let your healthcare team know right away. After they complete a thorough exam, extra testing may include:

• A complete blood count (to check for infection)

• Blood flow studies (to check for adequate blood flow to the legs)

• X-ray or computed tomography (CT) (to look for bone damage)

• Magnetic resonance imaging (MRI) (to look at surrounding tissues and structures)

• Bone biopsy (to find the bacteria causing foot infection)

• Angiography (to find and open any blocked arteries and improve blood flow)

Are diabetic foot ulcers serious?

Yes, diabetic foot ulcers can become a very serious problem — especially if they get infected. Unhealed ulcers are one of the most common foot problems leading to lower extremity amputations. Amputations can lead to significant disability.

Stages of diabetic foot ulcers

Diabetic foot ulcers go through six different stages. These stages help to classify how severe an ulcer is and how long it may take to heal: 

• Stage 1: A normal foot. You should focus on good footwear and taking good care of your feet.

• Stage 2: One or more risk factors for an ulceration is present. Your foot may have swelling or thickened skin. You might have neuropathy or decreased blood flow to your feet. 

• Stage 3: A foot with an ulcer. These ulcers need treatment to prevent infection. It’s also important to take the pressure off of the foot, so you may need an air cast or bed rest. 

• Stage 4: An infected foot. A surgical procedure may be needed to cut away infected tissue and drain pus. This may require hospitalization. 

• Stage 5: A foot with some gangrene. At this stage, there’s some dead tissue from infection or lack of blood flow. Treatment usually involves hospitalization, IV antibiotics and surgical intervention. 

• Stage 6: A foot that needs amputation. The damage is so severe that part or all of the foot needs to be removed. 

If you have diabetes, it’s important to regularly check your feet for any cracks, cuts, or changes in appearance. If you see any changes or feel foot pain, let your healthcare professional know. They can guide you on the next steps to take so you have the best chances for healing.

Treatment of diabetic foot ulcers

There are different approaches to treating diabetic foot ulcers. Your healthcare team will look at a few things to decide the best treatment: how deep the ulcer is, if there are problems with blood flow or nerves in your feet, and whether there’s an infection.

Diabetic foot ulcer treatment often involves a few different approaches.

Off-loading

This technique relieves pressure off of the wound. Bearing weight on a callus or ulcer makes it harder for the area to heal quickly. Off-loading is done with the support of a cast, specialized footwear, or a wheelchair. Footwear that’s designed for off-loading is also helpful for preventing future diabetic ulcers. 

Wound care

Wound care may involve cleaning the wound daily with sterile fluid or soap and water. Bandages or dressings need to be applied and changed daily to help keep the area clean and moist. 

Debridement

This involves the removal of dead or infected skin and tissue from the foot. A healthcare professional will debride the wound using surgery, chemical treatment, or mechanical methods (like wet-to-dry dressings). This helps improve healing and prevents infection. 

Antibiotics

Antibiotics are used to prevent or treat bacterial infection of a foot ulcer. Mild infections can be treated with oral antibiotics, including dicloxacillin, cephalexin, and clindamycin. More severe infections need IV antibiotics. These may include:

• Ciprofloxacin and clindamycin

• Piperacillin/tazobactam (Zosyn)

• Imipenem/cilastin 

Hyperbaric oxygen therapy

Hyperbaric oxygen therapy is a type of treatment in which a person breathes in 100% oxygen in a pressurized chamber. This boosts oxygen in the bloodstream, which may help with wound healing. Clinical guidelines recommend adding hyperbaric oxygen therapy for certain foot ulcers after debridement. This may improve healing and lower the risk of needing amputation. 

When to see a doctor

You should see a healthcare professional you trust if you see any signs on your foot that an ulcer might be developing. But you don’t need to wait for visible changes. Sometimes early signs of a problem show up with sensations like pain or tingling.

Reach out to a healthcare professional you trust if you experience any of the following:

• Dry, cracked skin on your feet

• Swelling or redness 

• Pain

• Tingling

• A change in the color or temperature of your feet

• Ingrown toenail

• Any sores, blisters, or ulcers

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Written by:

Bernadette Anderson, MD, MPH

A native of Saginaw, Michigan, Dr. Bernadette earned an undergraduate degree in psychology from the University of Michigan, Ann Arbor. She completed a master's degree in public health at the University of California, Berkeley, and a doctorate of medicine from the Medical College of Ohio.

Edited by:

Alex Eastman, PhD, RN

Alex Eastman, PhD, RN, is a California-based registered nurse and staff medical editor at GoodRx, where he focuses on clinical updates and Latino health.

Reviewed by:

Karen Hovav, MD, FAAP

Karen Hovav, MD, FAAP, has more than 15 years of experience as an attending pediatrician in a variety of clinical settings. She has worked in a large academic center in an urban city, a small community hospital, a private practice, and an urgent care clinic.

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